Leptin Stimulates Prolactin mRNA Expression in the Goldfish Pituitary through a Combination of the PI3K/Akt/mTOR, MKK3/6/p38MAPK and MEK1/2/ERK1/2 Signalling Pathways

Leptin actions at the pituitary level have been extensively investigated in mammalian species, but remain insufficiently characterized in lower vertebrates, especially in teleost fish. Prolactin (PRL) is a pituitary hormone of central importance to osmoregulation in fish. Using goldfish as a model, we examined the global and brain-pituitary distribution of a leptin receptor (lepR) and examined the relationship between expression of lepR and major pituitary hormones in different pituitary regions. The effects of recombinant goldfish leptin-AI and leptin-AII on PRL mRNA expression in the pituitary were further analysed, and the mechanisms underlying signal transduction for leptin-induced PRL expression were determined by pharmacological approaches. Our results showed that goldfish lepR is abundantly expressed in the brain-pituitary regions, with highly overlapping PRL transcripts within the pituitary. Recombinant goldfish leptin-AI and leptin-AII proteins could stimulate PRL mRNA expression in dose- and time-dependent manners in the goldfish pituitary, by both intraperitoneal injection and primary cell incubation approaches. Moreover, the PI3K/Akt/mTOR, MKK_3/6/p³⁸MAPK, and MEK_1/2/ERK_1/2—but not JAK2/STAT 1, 3 and 5 cascades—were involved in leptin-induced PRL mRNA expression in the goldfish pituitary.

Dynamic responses of prolactin, growth hormone and their receptors to hyposmotic acclimation in the olive flounder Paralichthys olivaceus

Prolactin (PRL) and growth hormone (GH) play important roles in regulating salt and water balance through osmoregulatory organs in vertebrates. The aim of this study was to investigate the dynamic changes of GH/PRL hormone gene expressions in the pituitary gland and their receptors in gill and kidney, as well as the plasma osmolality when the olive flounder fish Paralichthys olivaceus were acclimated in freshwater (FW) conditions. After transfer from seawater (SW) to freshwater (FW), the osmolality of FW-adaption fish reached the lowest level at 1d which rose slightly afterwards. However, the hormone gene expression of PRL increased from 2d, reaching its peak at 5d, and then decreased at 14d. At this time, the value was still significantly higher than the control, showing a similar trend to the plasma hormone PRL. In contrast, the pituitary mRNA level of GH significantly decreased at 1d and then returned to normal levels. The mRNA levels of PRL receptor (PRLR) in both gill and kidney displayed a similar trend to the pituitary PRL. We also observed the synchronous expression trend of the renal PRLR with pituitary PRL (5d) and the asynchronous expression peaks between branchial (8d) and renal PRLR (5d). Significant responses of GH and its receptor (GHR) in both gill and kidney during the FW-acclimation were not observed. Nevertheless, the gene expression of GH receptor variant (GHR-V) in both gill and kidney declined at 2d, indicating unknown osmoregulatory functions of GHR-V. Collectively, our results provided more insights of the PRL, GH and their corresponding receptors in modulating osmoregulatory responses, representing an important aspect of FW-acclimation in flounder fish.

BREEDING AND GENETICS SYMPOSIUM:Breeding heat tolerant dairy cattle: the case for introgression of the "slick" prolactin receptor variant into dairy breeds

Increasing environmental temperatures are a threat to the sustainability of livestock production and, because of the high metabolic demands of lactation, to dairy production in particular. Summer heat waves in temperate climates reduce feed intake, milk production, and cow comfort. In extreme heat events, there is an increase in cow mortality. In tropical climates, dairy cattle are mostly (zebu) type or zebu crossbred with temperate dairy breeds. Crossbreeding is undertaken to combine the heat tolerance and tick resistance of zebu with the productivity of temperate dairy breeds. In the absence of improved heat tolerance, milk production and fertility of temperate cattle is severely impaired. We have recently identified a key role for the prolactin pathway in regulating heat tolerance. A de novo mutation in prolactin that impairs prolactin activity was discovered in hairy and heat intolerant, New Zealand dairy cattle. The phenotypes produced were remarkably similar to those seen in fescue toxicosis, a syndrome seen in grazing cattle in the U.S. where ingestion of ergovaline, a fungal toxin from infected pasture, inhibits prolactin secretion. Recognition of the role of prolactin in hairy cattle led us to identify a deletion in exon 10 of the long-form of the prolactin receptor in Senepol cattle that causes truncation of the protein and determines the slick coat and heat tolerance traits found in this , beef breed. The short form of the prolactin receptor is predicted to be unaffected by the deletion. Knowledge of this dominant mutation has provided the impetus to begin a crossbreeding program to investigate performance and heat tolerance of temperate dairy cattle carrying the slick, prolactin receptor variant. The perceived opportunity is to introgress this variant into temperate dairy cattle to enable performance and welfare improvement in hot climates. Heat tolerance of cattle with slick coats appears to be mostly associated with coat type although sweating ability may also be enhanced. Further investigation is required of performance traits in cows homozygous for the slick variant because the published data are almost exclusively from heterozygous animals. Combination of the slick mutation with other favorable genes for heat tolerance, especially those for coat color, will be particularly enabled by gene editing technologies, offering opportunities for further improvement in bovine thermotolerance.

Comparative proteomic analysis of pituitary glands from Huoyan geese between pre-laying and laying periods using an iTRAQ-based approach

In this study, we performed a comprehensive evaluation of the proteomic profile of the pituitary gland of the Huoyan goose during the laying period compared to the pre-laying period using an iTRAQ-based approach. Protein samples were prepared from pituitary gland tissues of nine pre-laying period and nine laying period geese. Then the protein samples from three randomly selected geese within each period were pooled in equal amounts to generate one biological sample pool. We identified 684 differentially expressed proteins, including 418 up-regulated and 266 down-regulated proteins. GO annotation and KEGG pathway analyses of these proteins were conducted. Some of these proteins were found to be associated with hormone and neurotransmitter secretion and transport, neuropeptide signalling and GnRH signalling pathways, among others. Subsequently, the modification of the abundance of three proteins (prolactin, chromogranin-A and ITPR3) was verified using western blotting. Our results will provide a new source for mining genes and gene products related to the egg-laying performance of Huoyan geese, and may provide important information for the conservation and utilization of local goose breeds.

Effects of sex steroids on the pattern of methylation and expression of the promoter region of estrogen and androgen receptors in people with gender dysphoria under cross-sex hormone treatment

Cross-sex hormone therapy (CHT) is critical for phenotypical and physiological transition in adults with gender dysphoria (GD). However, the impact of the CHT onto the molecular level/epigenetic regulation has not been comprehensively addressed. We postulate that CHT in GD could drive changes at the androgen receptor (AR), estrogen receptor alpha (ESR1) and estrogen receptor beta (ESR2), affecting their DNA methylation pattern and mRNA expression that may influence in the phenotypical changes associated to CHT. We carried out a prospective observational study on individuals with a diagnosis of GD. 18 subjects (no previous CHT): 12 female to male (FtoM) and 6 male to female (MtoF). An Epityper Mass array TM method was used to study the DNA methylation and Real-time PCR quantitative reverse transcription PCR (qRT-PCR) was used to quantify the gene expression. The analysis of AR, ESR1 and ESR2 receptor was performed at baseline, 6 and 12 months after CHT. No differences in DNA methylation of ESR were found in MtoF, while DNA methylation was increased in FtoM at 6 and 12 months of CHT. The AR showed a significant increase of methylation in MtoF group after 12 months of estrogenic treatment. Regarding the expression analysis, AR expression was significantly decreased in FtoM upon CHT treatment. AR, ESR1 and ESR2 methylation were correlated with anthropometric, metabolic and hormonal parameters in FtoM and MtoF. Our results support that CHT is associated to epigenetic changes that might affect the response to treatment with sex steroids.

Origin of a rapidly evolving homeostatic control system programming testis function

Mammals share common strategies for regulating reproduction, including a conserved hypothalamic-pituitary-gonadal axis; yet, individual species exhibit differences in reproductive performance. In this report, we describe the discovery of a species-restricted homeostatic control system programming testis growth and function. Prl3c1 is a member of the prolactin gene family and its protein product (PLP-J) was discovered as a uterine cytokine contributing to the establishment of pregnancy. We utilized mouse mutagenesis of Prl3c1 and revealed its involvement in the regulation of the male reproductive axis. The Prl3c1-null male reproductive phenotype was characterized by testiculomegaly and hyperandrogenism. The larger testes in the Prl3c1-null mice were associated with an expansion of the Leydig cell compartment. Prl3c1 locus is a template for two transcripts (Prl3c1-v1 and Prl3c1-v2) expressed in a tissue-specific pattern. Prl3c1-v1 is expressed in uterine decidua, while Prl3c1-v2 is expressed in Leydig cells of the testis. 5'RACE, chromatin immunoprecipitation and DNA methylation analyses were used to define cell-specific promoter usage and alternative transcript expression. We examined the Prl3c1 locus in five murid rodents and showed that the testicular transcript and encoded protein are the result of a recent retrotransposition event at the Mus musculus Prl3c1 locus. Prl3c1-v1 encodes PLP-J V1 and Prl3c1-v2 encodes PLP-J V2. Each protein exhibits distinct intracellular targeting and actions. PLP-J V2 possesses Leydig cell-static actions consistent with the Prl3c1-null testicular phenotype. Analysis of the biology of the Prl3c1 gene has provided insight into a previously unappreciated homeostatic setpoint control system programming testicular growth and function.

Prolactin function and putative expression in the brain

INTRODUCTION

Prolactin is a peptide hormone mainly synthetized and secreted by the anterior pituitary gland, but also by extrapituitary tissues, such as mammary gland, decidua, prostate, skin, and possibly the brain. Similarly, prolactin receptor is expressed in the pituitary gland, many peripheral tissues, and in contrast to prolactin, its receptor has been consistently detected in several brain regions, such as cerebral cortex, olfactory bulb, hypothalamus, hippocampus, amygdala, among others. Classically, prolactin function has been related to the stimulation of lactogenesis and galactopoiesis, however, it is well known that prolactin induces a wide range of functions in different brain areas.

PURPOSE

The aim of this review is to summarize recent reports on prolactin and prolactin receptor synthesis and localization, as well as recapitulate both the classic functions attributed to this hormone in the brain and the recently described functions such as neurogenesis, neurodevelopment, sleep, learning and memory, and neuroprotection.

CONCLUSION

The distribution and putative expression of prolactin and its receptors in several neuronal tissues suggests that this hormone has pleiotropic functions in the brain.

Paeoniflorin and liquiritin, two major constituents in Chinese herbal formulas used to treat hyperprolactinemia-associated disorders, inhibits prolactin secretion in prolactinoma cells by different mechanisms

ETHNOPHARMACOLOGICAL RELEVANCE

Paeoniflorin and liquiritin are major constituents in some Chinese herbal formulas, such as Yiru Tiaojing (YRTJ) Granule (a hospitalized preparation) and Peony-Glycyrrhiza Decoction, used for hyperprolactinemia-associated disorders.

AIM OF THE STUDY

To investigate the effect of paeoniflorin and liquiritin on prolactin secretion.

MATERIALS AND METHODS

The effect of YRTJ Granule on metoclopramide-induced hyperprolactinemia was tested in rats. Paeoniflorin and liquiritin in the YRTJ Granule extract were identified and quantified by HPLC. The effects of paeoniflorin and liquiritin on prolactin secretion were examined in prolactinoma cells that were identified morphologically and by Western blot. The concentration of prolactin was determined by ELISA. The gene expression was analyzed by Western blot.

RESULTS

YRTJ Granule ameliorated metoclopramide-induced hyperprolactinemia in rats. The contents of paeoniflorin and liquiritin in YRTJ Granule were 7.43 and 2.05mg/g extract, respectively. Paeoniflorin, liquiritin and bromocriptine (a dopamine D₂ receptor (D₂R) agonist) decreased prolactin concentration in MMQ cells expressing D₂R. However, the effect of liquiritin and bromocriptine was abolished in GH3 cells lacking D₂R expression. Interestingly, paeoniflorin still decreased prolactin concentration in GH3 cells in the same manner. Furthermore, paeoniflorin suppressed prolactin protein expression, and was without effect on D₂R protein expression in both MMQ and GH3 cells.

CONCLUSIONS

The present results suggest that paeoniflorin and liquiritin play a role in YRTJ Granule-elicited improvement of hyperprolactinemia. While the effect of liquiritin is D₂R-dependent, paeoniflorin D₂R-independently inhibits prolactin secretion in prolactinoma cells that may especially benefit the hyperprolactinemic patients who are refractory to dopaminergic therapies.

Sex-Related Characteristics of Systemic Hormonal Homeostasis in Rats with Sarcoma C-45 Cells Transplanted to the Lung

Sex-related systemic status of pituitary and thyroid hormones and cortisol was studied in rats on days 7 and 14 after transplantation of sarcoma C-45 cells into the lung. Females demonstrated slower development of the tumor process (49.0±10.7 vs. 32.0±3.9 days in males). Injection of tumor cells causes similar disorders in the levels of ACTH, thyrotropic hormone, and prolactin in males and females and opposite disorders in the thyroid and glucocorticoid homeostasis associated in males (in contrast to females) with reduction of cortisol level (by 1.9 times) and increase in the concentrations of total thyroxine forms (by 1.4 times) and triiodothyronine (by 2.9 times) by day 14. Early sex-related shifts in the status of hormone that are a component of the adaptive system attest to their possible relationship with different course of the malignant process in male and female rats.

Mechanisms for PACAP-induced prolactin gene expression in grass carp pituitary cells

In mammals, pituitary adenylate cyclase-activating polypeptide (PACAP) is a pleiotropic hormone with diverse functions but its role in prolactin (PRL) regulation is highly controversial. To shed light on Prl regulation by PACAP in fish model, grass carp pituitary cells was used as a model to examine the receptor specificity and signal transduction for PACAP modulation of prl gene expression in the carp pituitary. Using RT-PCR, PACAP-selective PAC1 receptor was detected in carp lactotrophs. In carp pituitary cells, nanomolar doses of PACAP, but not VIP, could elevate Prl secretion and protein production with concurrent rise in prl mRNA and these stimulatory effects were blocked by PACAP antagonist but not VIP antagonist. PACAP-induced prl mRNA expression could be mimicked by activating adenylate cyclase (AC), increasing cAMP level by cAMP analog, or increasing intracellular Ca²⁺ ([Ca²⁺]i) by Ca²⁺ ionophore/voltage-sensitive Ca²⁺ channel (VSCC) activator. PACAP-induced prl gene expression, however, was attenuated/abolished by suppressing cAMP production, inhibiting PKA activity, blocking [Ca²⁺]i mobilization and VSCC activation, calmodulin (CaM) antagonism, and inactivation of JNK and CaM Kinase II (CaMK-II). Similar sensitivity to CaM, JNK, and CaMK-II blockade was also noted by substituting cAMP analog for PACAP as the stimulant for prl mRNA expression. These results, as a whole, provide evidence for the first time that (i) PACAP activation of PAC1 receptor expressed in carp lactotrophs could induce Prl synthesis and secretion, and (ii) Prl production induced by PACAP was mediated by upregulation of prl gene expression, presumably via functional coupling of cAMP/PKA-, Ca²⁺/CaM-, and MAPK-dependent cascades.

Chronic endometritis modifies decidualization in human endometrial stromal cells

BACKGROUND

Chronic endometritis (CE) is a continuous inflammation of uterine endometrium, and it is usually symptomless. As CE has been thought not to affect the reproductive status and general health of affected women, its significance has not been explored. However, recent studies have shown that CE is related with repeated implantation failures after in vitro fertilization-embryo transfer, unexplained infertility, and recurrent miscarriages. As decidua differentiates to support the implantation process and maintains the pregnancy, we hypothesized that CE may influence the process of decidualization.

METHODS

Seventeen patients were employed in the experiment involving culture of endometrial stromal cells (ESCs). After obtaining endometrial samples, ESCs were harvested and cultured for 13 days. The concentrations in culture media and the protein expressions in ESCs of prolactin (PRL) and insulin-like growth factor binding protein-1 (IGFBP-1), two well known decidualization markers used in a large number of in vitro models, were analyzed by ELISA and Western blotting, respectively, and the cell numbers were also counted. The mRNA levels of PRL and IGFBP-1 were tested by quantitative real time polymerase chain reaction (RT-PCR). Since sex hormone induce proliferation and differentiation to decidua via binding to the sex hormone receptors (ERα, ERβ, PRA, and PRB), their expression was assessed in another 17 patients' paraffin-embedded endometrial tissue specimens by immunohistochemistry and semi-quantified by H-score.

RESULTS

Increased cell numbers and reduced secretion of PRL and IGFBP-1 were detected by ELISA in the ESCs of CE patients after culture for 13 days compared with non-CE patients. The decreased protein expression of IGFBP-1 in ESCs of CE patients was detected by Western blotting. The decreased expression of PRL mRNA and IGFBP-1 mRNA were detected by RT-PCR. Increased expressions of ERα, ERβ, PRA, and PRB were observed in the stromal cells of CE patients in comparison to non-CE patients, whereas increased expressions of ERα and ERβ were detected in the glandular cells of CE.

CONCLUSION

Our data suggests that CE modifies decidualization of human ESC through untuning the function of sex steroid hormone receptor.

Decidualization is Impaired in Endometrial Stromal Cells from Uterine Rudiments in Mayer-Rokitansky-Küster-Hauser Syndrome

BACKGROUND/AIMS

Uterine rudiments from patients with Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS) contain all tissues typically found in the uterus. Endometrium from the rudiments predominantly exhibits basalis-like features, and endometrial proliferative capacity in patients' epithelium and stroma is significantly lower.

METHODS

This single-center, prospective study conducted at a major German university hospital compared in-vitro decidualization in cultured ESCs from MRKHS patients and hysterectomy controls. Primary ESC cultures were established from both sources. Hormone-induced prolactin and IGFBP-1 secretion served as a measure of their ability to undergo decidualization in response to hormonal stimulation. Expression levels of 8 key marker genes of decidualization were also determined.

RESULTS

At day 9, mean secretion of prolactin and IGFBP-1 was significantly reduced by 89.0% and 99.5%, respectively, in MRKHS ESCs vs. hysterectomy controls, both indicating impaired decidualization of MRKHS ESCs. Key decidual markers confirmed impaired decidualization in MRKHS patients.

CONCLUSION

Our results indicate that the ESCs from MRKHS patients lack hormone responsiveness as a potential sign of dysfunctional hormone receptor function, which may also play a role in the onset of MRKHS. Further studies are needed to corroborate our findings, directly address receptor function, and elucidate the role of other potential determinants of uterine development and adult function.

Short communication: Identification of variation in the ovine prolactin gene of Chios sheep with a cost-effective sequence-based typing assay

The present study identified single nucleotide polymorphisms (SNP) in the coding and untranslated regions of the ovine prolactin gene of Chios sheep. By developing a cost-effective direct sequence-based typing assay, around 600 bp of reliable sequencing data and clear identification of heterozygous positions was achieved. Five SNP were found, located in exons 2 (KC764410:g.567G>A, g.625C>T, g.683C>A) and 3 (KC764410:g.2015C>A, g.2101G>A), whereas the remaining exons were monomorphic. The identified SNP were synonymous, with the exception of the g.567G>A SNP, which results in an Arg to His amino acid change. As the sequencing cost of the sequence-based typing assay was 20 orders of magnitude lower compared with a standard Sanger method, the assay was also used as a genotyping tool. The identified polymorphism was genotyped for 247 ewes and was subsequently used in mixed model association analyses of milk yield, milk fat content, and litter size at birth. The association analysis revealed a significant dominance effect of 0.17 ± 0.07 of the g.2015C>A SNP on milk fat percentage, whereas a dominance effect of -21.33 ± 10.51 of the same SNP on total lactation milk yield was also estimated. The g.2015C>A SNP explained 2.47 and 3.68% of the total phenotypic variance of milk yield and milk fat percentage, respectively, whereas the corresponding values for the animal variance were 7.14 and 11.75%. A suggestive association of the nonsynonymous g.567G>A SNP with litter size at birth was also detected.

Molecular performance of Prl and Gh/Igf1 axis in the Mediterranean meager, Argyrosomus regius, acclimated to different rearing salinities

Aquaculture industry in the Mediterranean region exhibits a growing interest for the Mediterranean meager Argyrosomus regius. Some preliminary works showed a good growth performance of the species in nearly isosmotic salinities. However, the patterns of alteration of prolactin (Prl) as well as growth hormone (Gh)/insulin growth factor-1 (Igf1) axis at the molecular level are not yet described in this species. Therefore, we cloned and sequenced partial cDNAs for pituitary prolactin (prl) and growth hormone (gh), hepatic insulin-like growth factor (igf1), and β-actin (actb). Expression patterns of these transcripts were tested in juveniles of A. regius acclimated to four different environmental salinities: (1) 5 ‰ (hyposmotic); (2) 12 ‰ (isosmotic); (3) 38 ‰ (hyperosmotic; seawater control); and (4) 55 ‰ (extremely hyperosmotic). All investigated transcripts shared high sequence identities with their counterparts in other perciformes. prl mRNA levels showed inverse pattern with increasing salinities. gh mRNA enhanced significantly in both 12 and 55 ‰ salinity groups in comparison with the control group, while igf1 showed its maximum expression levels under the nearly isosmotic environment. The results indicated clear sensitivity of prl, gh and igf1 to changes in environmental salinity, which can possibly control the euryhalinity capacity of this species.

Prolactin role in the bovine uterus during adenomyosis

Adenomyosis is uterine dysfunction defined as the presence of endometrial glands within the myometrium. It is suggested that adenomyosis is estrogen-dependent pathology, and prolactin (PRL) also affects its development. In the uterus of ruminants, PRL stimulates gland proliferation and function. We hypothesized that in the bovine uterus, the expression of PRL and its receptors (PRLRs) during adenomyosis is disturbed and modulated by estradiol (E₂). Uterine tissues were collected postmortem from cows; epithelial, stromal, and myometrial cells were isolated; and cultured and treated with E₂. Material was divided into 2 groups: control (nonadenomyotic) and uteri with adenomyosis. In adenomyotic uterine tissue, PRL and its long-form receptor protein were increased, as determined by Western blotting. Immunohistostaining showed that during adenomyosis, PRL and its receptors are highly expressed in adenomyotic lesions. In cultured myometrial cells, protein expression of PRL and its receptors was increased during adenomyosis. Estradiol decreased PRLRs protein expression in nonadenomyotic stromal cells and in adenomyotic myometrial cells, and increased PRL secretion by adenomyotic myometrial cells. Moreover, PRL secretion was increased in untreated epithelial and stromal cells during adenomyosis. On the other hand, in stromal cells, PRLRs messenger RNA and protein expression was decreased, as determined by real-time PCR and Western blotting, respectively. Obtained results show that significant changes in PRL and PRLRs expression are observed in uterine tissue and cells during adenomyosis, which were also affected by E₂. These data suggest involvement of PRL in adenomyosis development and the link between PRL and E₂ actions during the dysfunction in cows.

[Sensitivity of T-Lymphocytes to Hormones of the Anterior Pituitary Gland]

The review provides information about the features of the sensitivity of thymocytes, lymphoid organs' cells and T-lymphocytes of peripheral blood to the hormones secreted by anterior pituitary gland's cells: growth hormone, thyrotropin, adrenocorticotropic hormone, prolactin and β-endorphin. Some aspects of the T-lymphocytes's response to humoral signals from the hypophysis are shown in the article. Also the pituitary hormones' role in the regulation of proliferation, differentiation, and cytokine production of T-lymphocytes in normal and pathological conditions of the organism being discussed.

Expression and regulation of prolactin-like protein messenger RNA in undifferentiated chicken granulosa cells

Prolactin-like protein (PRL-L; LOC417800) is a homolog of PRL in non-mammalian vertebrates and can act as a functional ligand of PRL receptor (PRLR). Despite its widespread expression in extrapituitary tissues, mechanisms of regulation of PRL-L in the chicken ovary remain unknown. In this study, we first examined PRL-L expression in chicken ovarian developing follicles. PRL-L transcript levels were highest (P<0.05) in follicular walls of <2mm follicles and progressively declined during follicle maturation. Undifferentiated granulosa cells of 6-8mm follicles had higher (P<0.05) PRL-L mRNA levels than differentiated granulosa cells of F3, F2 or F1 follicles. In cultured undifferentiated granulosa cells, levels of PRL-L transcript were increased (P<0.05) by follicle stimulating hormone (FSH) treatment while were not altered by the addition of luteinizing hormone (LH). In addition, 10ng/ml non-glycosylated (NG-) and 1ng/ml glycosylated (G-) PRL increased (P<0.05) but at higher levels (100 or 1000ng/ml) both showed no effects on PRL-L expression. Furthermore, 100ng/ml NG-PRL enhanced (P<0.05) FSH-induced PRL-L expression, whereas the effects of G-PRL were not significant. These results suggest that PRL-L mRNA is differentially expressed in the follicular hierarchy and its high abundance in undifferentiated granulosa cells is under the regulation of FSH or PRL variants independently or in combination. Moreover, in undifferentiated granulosa cells we also provide evidence for a positive role for PKA, PKC and PI3K signaling while a negative role for ERK2 in mediating FSH stimulation of PRL-L transcription.

Effects of High-Fat Diet on Stress Response in Male and Female Wildtype and Prolactin Knockout Mice

Prolactin (PRL) is well characterized for its roles in initiation and maintenance of lactation, and it also suppresses stress-induced responses. Feeding a high-fat diet (HFD) disrupts activity of the hypothalamic-pituitary-adrenal (HPA) axis. Whether PRL regulates HPA axis activation under HFD feeding is not clear. Male and female wildtype (WT) and PRL knockout (KO) mice were fed either a standard low-fat diet (LFD) or HFD for 12 weeks. Circulating corticosterone (CORT) levels were measured before, during, and after mice were subjected to an acute restraint stress or remained in their home cages as no stress controls. HFD feeding increased leptin levels, but the increase was lower in KO than in WT mice. All stressed female groups and only LFD-fed stressed males had elevated CORT levels compared to their no stress same-sex counterparts regardless of genotype. These results indicated that HFD consumption blunted the HPA axis response to acute stress in males but not females. Additionally, basal hypothalamic CRH content was lower in HFD than LFD males, but was similar among female groups. Furthermore, although basal CORT levels were similar among KO and WT groups, CORT levels were higher in KO mice than their WT counterparts during stress, suggesting that loss of PRL led to greater HPA axis activation. Basal PRL receptor mRNA levels in the choroid plexus were higher in HFD than LFD same-sex counterparts, suggesting activation of central PRL’s action by HFD feeding in both males and females. Current results confirmed PRL’s roles in suppression of the stress-induced HPA axis activation. Although HFD feeding activated central PRL’s action in both sexes, only the male HPA axis was dampened by HFD feeding.

Prolactin receptor in breast cancer: marker for metastatic risk

Prolactin and prolactin receptor signaling and function are complex in nature and intricate in function. Basic, pre-clinical and translational research has opened up our eyes to the understanding that prolactin and prolactin receptor signaling function differently within different cellular contexts and microenvironmental conditions. Its multiple roles in normal physiology are subverted in cancer initiation and progression, and gradually we are teasing out the intricacies of function and therapeutic value. Recently, we observed that prolactin has a role in accelerating the time to bone metastasis in breast cancer patients and identified the mechanism by which prolactin stimulated breast cancer cell-mediated lytic osteoclast formation. The possibility that the prolactin receptor is a marker for metastasis, and specifically bone metastasis, is one that may have to be put into the context of the different variants of prolactin, different prolactin receptor isoforms and intricate signaling pathways that are regulated by the microenvironment. The more complete the picture, the better one can test biomarker identity and design clinical trials to test therapeutic intervention. This review will cover the recent advances and highlight the complexity of prolactin receptor biology.

Genomic analyses identify agents regulating somatotroph and lactotroph functions

Isolated hormone deficiency might be caused by loss of a specific type of endocrine cells, and regenerating these missing cells may provide a new option for future treatment. It is known that POU1F1 lineage cells can differentiate into thyrotroph, somatotroph, and lactotroph. However, there is no effective way of controlling pituitary stem/progenitor cells to differentiate into a specific type of endocrine cell. We thereby analyzed multiple genomic publications related to POU1F1 and pituitary development in this study to identify genes and agents regulating POU1F1 lineage cell differentiation. ANOVA analyses were performed to obtain differentially expressed genes. Ingenuity pathway analyses were performed to obtain signaling pathways, interaction networks, and upstream regulators. Venn diagram was used to determine the overlapping information between studies. Summary statistics was performed to rank genes according to their frequency of occurrence in these studies. The results from upstream analyses indicated that 326 agents may regulate pituitary cell differentiation. These agents can be categorized into 12 groups, including hormones and related pathways, PKA-cAMP pathways, p53/DNA damaging/cell cycle pathways, immune/inflammation regulators, growth factor and downstream pathways, retinoic/RAR pathways, ROS pathways, histone modifications, CCAAT/enhancer binding protein family, neuron development/degeneration pathways, calcium related and fat acid, and glucose pathways. Additional experiments demonstrated that H₂O₂ and catalase differentially regulate growth hormone and prolactin expression in somatolactotroph cells, confirming potential roles of ROS pathway on regulating somatotroph and lactotroph functions.

Increased Expression of TLR4 and TLR7 but Not Prolactin mRNA by Peripheral Blood Monocytes in Active Celiac Disease

BACKGROUND

Celiac disease (CD) is an organ-specific autoimmune disease, and both adaptive and innate immunity are involved in its development.

OBJECTIVES

The aim of the study was to determine whether the markers of intestinal mucosal inflammation in CD can be detected in peripheral blood monocytes (PBMs), and whether the immune properties of PBMs change as the clinical signs and symptoms of CD improve after the introduction of a gluten-free diet (GFD). The focus was on changes in mRNA expression of selected toll-like receptors (TLR2, TLR4, TLR7), stress cytokine prolactin (PRL), and proand anti-inflammatory cytokines (TNF-α, IL-6, IL-12, IL-10) in PBMs.

MATERIAL AND METHODS

The study involved 20 CD patients diagnosed according to the European Society for Pediatric Gastroenterology, Hepatology and Nutrition criteria and Marsh criteria: 10 recently-diagnosed cases (rCD) and 10 on a GFD for a minimum of one year. The control group comprised 10 ageand sex-matched healthy volunteers. PBMs from peripheral blood specimens were separated using immunomagnetic CD14+ beads. Total RNA was isolated using a standard commercial kit. Cytokine and TLR mRNA levels were quantified by relative qPCR with PGK1 as a reference gene.

RESULTS

Significantly higher expression of TLR4 and TLR7 mRNA was observed in PBMs from rCD patients compared to the healthy controls (1.63 times higher; p < 0.05). TLR7 mRNA levels in rCDs were also significantly elevated in comparison to the CD-GFD patients (2.11 times higher; p < 0.01). TNF-α mRNA expression tended to be higher in both groups of patients; by contrast, in IL-6 mRNA, a trend to a fourfold decrease was detected in PBMs from the CD-GFD subjects. IL-10, IL-12 and PRL levels did not differ among the groups.

CONCLUSIONS

The data suggest that the inflammatory process in rCD intestinal mucosa and submucosa reflecting enterocyte damage can be detected in PBMs in peripheral blood. Further, the cytokine and TLR expression profile in PBMs alters after one year of GFD treatment.

Progestagenic Effects of Tibolone are Target Gene—Specific In Human Endometrial Cells

OBJECTIVES

Tibolone (Tib) exhibits progestagenic activities in addition to its tissue-specific estrogenic activities. The purpose of the current study was to determine the progestagenic actions of Tib and its metabolites using target genes known to be regulated by progestins in human endometrial glandular and stromal cells.

METHODS

Human endometrial glandular and stromal cells were isolated from endometrial tissue fragments and separately incubated with Tib and its metabolites. Real-time polymerase chain reaction (PCR) was used to determine the mRNA content of 17betahydroxy steroid dehydrogenase (17betaHSD, type 2) and sulfotransferase (SULT1E1) in endometrial glandular cells, and prolactin (PRL) and insulin-like growth factor binding protein-1 (IGFBP1) in endometrial stromal cells.

RESULTS

In glandular cells, Tib and Delta4-tibolone (Delta4Tib) significantly increased the content of 17betaHSD and SULT1E1 mRNA. In stromal cells, Tib and Delta4Tib increased PRL mRNA ( approximately 30% of the capacity compared to progesterone) and had little effect on IGFBP1 mRNA. Anti-progestin, RU486, reversed the induction of SULT1E1 and PRL by progesterone or Tib. Also, the two 3 hydroxyl tobolone metabolites, especially 3betaOHTib, showed some progestagenic effects.

CONCLUSIONS

The data showed that Tib and Delta4Tib exhibited clear progestagenic effects in endometrial glandular cells by inducing 17betaHSD and SULT1E1, while in stromal cells the response was weaker in the induction of PRL and had little effect on IGFBP1. In addition, the 3betaOHTib metabolite expressed progestagenic activity. These disparate effects in two types of cells may be beneficial for maintaining endometrial cells in a quiescent state.

Molecular endocrine changes of Gh/Igf1 axis in gilthead sea bream (Sparus aurata L.) exposed to different environmental salinities during larvae to post-larvae stages

The influence of acclimation of the euryhaline gilthead sea bream (Sparus aurata) larvae/post-larvae to brackish water on growth, energetic contents, and mRNA levels of selected hormones and growth-regulating hypothalamic neurohormones was assessed. Specimens from 49 days post-hatching were acclimated during 28 days to two different environmental salinities: 38 and 20 psu (as brackish water). Both groups were then transferred to 38 psu and acclimated for an additional week. Early juveniles were sampled after 28 days of acclimation to both salinities and one week after transfer to 38 psu. Pituitary adenylate cyclase-activating peptide (adcyap1; pacap), somatostatin-I (sst1), growth hormone (gh1), insulin-like growth factor-I (igf1), and prolactin (prl) mRNA expression were all studied by QPCR. Post-larvae acclimated to 20 psu showed better growth performance and body energetic content than post-larvae maintained at 38 psu. prl, adcyap1, and igf1 mRNA expression levels increased in 20-psu-acclimated post-larvae but decreased upon transfer to 38 psu. GH1 expression did not show significant changes under both experimental conditions. Our results suggested an enhanced general performance for post-larvae in brackish water, supported by the actions of adcyap1, igf1, and prl.

Three-dimensional Imaging of the Intracellular Localization of Growth Hormone and Prolactin and Their mRNA Using Nanocrystal (Quantum Dot) and Confocal Laser Scanning Microscopy Techniques

Semiconductor nanocrystals (Quantum dots, Qdots) have recently been used in biological research, because they do not fade on exposure to light, and they enable us to obtain multicolor imaging because of a narrow emission peak that can be excited via a single wavelength of light. There have been no reports of simultaneous localization of mRNA and protein using Qdots. We successfully applied these advantages of Qdot and confocal laser scanning microscopy (CLSM) to three-dimensional images of the intracellular localization of growth hormone and prolactin and to their mRNA. In situ hybridization and immunohistochemistry using Qdots combined with CLSM can optimally illustrate the relationship between protein and mRNA simultaneously in three dimensions. Such an approach enables us to visualize functional images of proteins in relation with mRNA synthesis and localization.

POLYMORPHISM OF THE PROLACTIN GENE AND ITS EFFECT ON FIBER TRAITS IN GOAT

The prolactin gene (PRL) is a potential candidate gene for the goat cashmere traits in marker-assisted selection. Thus, the aim of this study was to detect PRL gene polymorphism and its association with fiber traits in 200 Raini cashmere goats native to the south-east of Iran. A 196-bp fragment encoding exon 5 within the goat PRL gene was amplified using PCR specific primers. The amplification products were subjected to the single stranded conformation polymorphism (SSCP) analysis. Three different SSCP banding patterns (CC, AC and AA) were observed in exon 5 of the caprine PRL gene. The pattern frequencies for CC, AC and AA were 0.39, 0.38 and 0.23 and frequencies of the A and C alleles were 0.42 and 0.58, respectively. The genotypic distributions did not deviate from the Hardy-Weinberg equilibrium (P> 0.05). The number of observed alleles, number of effective alleles, expected heterozygosity, observed heterozygosity, mean of heterozygosity, expected homozygosity, observed homozygosity, Nei's index and Shanon's index were 2.0, 1.9, 0.48, 0.38, 0.48, 0.51, 0.61, 0.48 and 0.68, respectively. Results of association between genotypes and fiber traits indicated that the CC genotype had the highest fiber length compared with the AA and AC genotypes (P < 0.05) while there was no significant association between the PRL gene genotypes and fiber diameter. These results imply that the PRL gene polymorphism can be used as a molecular marker to improve fiber production without a negative effect on fiber diameter.